they could be catabolized once metabolism has been restored. These molecules are typically nutrients i.e. Spore germination begins at the molecular level with germinants, low-molecular-weight molecules, which are recognized by the dormant spore as a signal that the environment is suitable to support cellular growth and replication. Welkos, in Molecular Medical Microbiology (Second Edition), 2015 Germination Initiation 31 It is important to determine the cause of incomplete germination and inactivation of spores by HPP so that this nonthermal processing technology can be more widely utilized by the food industry.Ĭhristopher K.
More recently, it was discovered that the level of germinant receptors on the spore’s inner membrane, levels of a small protein that may be a germinant receptor subunit, and a gerD mutation may affect superdormant spore germination by moderate high pressure. 8 It is an important finding for the food industry that superdormant spores are not the cause of incomplete germination of Bacillus species by HPP.
8 The findings of this study were significant in that the factors responsible for spore germination by pressure were not identical to those responsible for spore superdormancy or nutrient germination. More interestingly, superdormant spores germinated normally at 150 MPa, which was surprising to the authors because spore germination induced at this level of pressure requires activation of the nutrient germinant receptors, and spore germination induced by this level of pressure is increased by prior heat activation. According to these authors, this result was expected since spore germination at this level of pressure does not require activation of nutrient germinant receptors.
cereus that were not exposed to heat activation germinated normally, or similar to the rest of the spore population, at a pressure of 500 MPa. In a study by Wei et al., 8 superdormant spores of B. 46–48,51 Therefore it would be expected that superdormant spores, which have a decreased number of germinant receptors, would germinate poorly with low or moderate pressures. Since spore germination with moderate pressures is triggered by activation of nutrient receptors, spores with an increased number of germinant receptors will be more easily inactivated by moderate pressures. Hoover, in The Diverse Faces of Bacillus cereus, 2016 Superdormant Spores
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